Variable resistance flexion and extension exercise machine

ABSTRACT

An exercise machine including a frame and a drive arm pivotedly engaged to the frame, for example, on an upright thereof. A cylinder is mounted at one point to the frame and, at a removed end of a plunger, has links or rod members to engage the removed end of the plunger to the frame and also to the drive arm.

FIELD OF THE INVENTION

Flexion and extension exercise machine, more specifically a flexion and extension exercise machine having hydraulic or other resistance means with a fixed and a moveable end, the moveable end fixed by a link to two points, one a point on a frame and the second a point on a user actuated drive arm.

BACKGROUND OF THE INVENTION

Common exercise machines work specific muscle groups by resisting motion in a single degree of freedom, generalized direction. Typically, power is transmitted cyclically over the range of joint motion from the user's muscles, to the skeleton, through the machine interface and mechanical linkage, to the resistance mechanism. The resistance mechanism may be a guided weight, spring, friction belt, hydraulic cylinder or the like.

Biomechanical factors, such as force-length and force-velocity properties of muscle (Zajac 1989), muscle moment arms, and skeletal geometry, influence the capacity of the user to produce force in the generalized direction. These factors result in a generalized strength for the user on a particular machine which varies with both position and velocity over the range of exercise motion. Similarly, the resistance response of the machine may vary with position and velocity due to the mechanical advantage (MA) of the linkage and the properties of the resistance mechanism.

Typical prior art flexion and extension machines such as those used for elbows are illustrated in FIGS. 1A through 1C. They include a drive arm moveable with respect to a frame, the frame typically including upright. The drive arm is pivotally connected to the frame and, the removed end will engage the user's wrist or hand area, which will activate and pivot the drive arm. Since the drive arm is attached to a resistance mechanism, such as weights, springs or a hydraulic cylinder (as shown in FIGS. 1-3), the user must overcome the resistence.

Prior art machines link, for example, a hydraulic cylinder, a fixed point on the cylinder body pivotally to the frame and a point on the removed end of the rod of the hydraulic cylinder to the drive arm. This gives the benefit of balancing user strength and machine resistance by providing variable resistance. Some other existing exercise equipment, such as a Nautilus, employs cables, cams and weight to provide an appropriate variable resistance. In the prior art, “2-bar linkage designs” as set forth in FIGS. 1A and 1B (the two bars being the upright and the pivoting drive arm), at flexion angles between about 0 and 60 degrees (flexion angle measured between the user's upper arm and lower arm), mechanical advantage of the system increases, then from 60 degrees to about 120 degrees the MA decreases. Thus, variable resistance is achieved.

This “low-high-low” mechanical advantage change as the flexion angle changes between about zero and about 120 degrees tends to balance the generalized strength of the typical user, who is weaker at the lower angles, stronger around 60-80 degrees and then weaker again at high flexion angles greater than about 60-80 degrees. Thus, the variable resistance machine such as the 2-bar design illustrated in FIGS. 1A through 1C tends to provide greatest resistance when generalized muscle strength is greatest (60-80 degrees) and less resistance (through lower mechanical advantage) where muscle strength is weaker.

However, Applicant provides a novel linkage that yields better balance in a variable resistance 4-bar pivoting drive arm exercise machine in order to optimize exercise benefits.

Applicant achieves these results in a novel 4-bar flexion and extension machine which typically comprises a hydraulic cylinder having a movable plunger or piston and a hydraulic cylinder body. The hydraulic cylinder body is pivotally attached to a stationary frame or an upright. Also attached to the upright is a pivoting drive arm, actuated by the exerciser machine user. The removed end of the plunger is located, by links, pivotally, to both the stationary frame or upright and the pivoting drive arm.

The result is an improved exercise machine that better balances the variable resistance provided by the machine to the typical general muscle strength variation of user so as to achieve balance and smoothness of movement and consistency of velocity over the desired range of motion.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B and 1C illustrate side, front and top elevational views respectively of prior art “2-bar” elbow flexion and extension exercise machines.

FIGS. 2, 2A, 3 and 4 illustrate Applicant's novel “4-bar” flexion and extension exercise machine in side, side front and top elevational views respectively.

FIGS. 5, 6 and 7 represent side elevational, front elevational and top elevational views respectively of an alternate preferred embodiment of Applicant's novel invention, wherein the removed end of the plunger is attached to the rocker link.

FIGS. 8, 9 and 10 illustrate yet another novel embodiment of Applicant's flexion and extension exercise device, in side, front and top elevational views respectively, illustrating the removed end of the plunger attached to the coupler link.

FIG. 11 illustrates a preferred alternate embodiment of Applicant's exercise device showing a side-by-side arrangement of the arm or wrist engagement assembly so a user may use one assembly for the left arm and the other for the right arm.

BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT

Exercise device (10) is provided, more specifically exercise device (10) for providing variable resistance to flexion and extension motion in the limb of the exercise machine operator.

Exercise device (10) includes a fixed upright (12), typically anchored to or part of a frame attached to or supported by the floor. Pivotally attached to fixed upright (12) is a drive arm (14), the drive arm (14) having a near end (14A) and a removed end (14B). A hand, wrist or distal end of the forearm may engage the removed end of the drive arm to move it pivotally between a position represented by extension of the forearm and a position represented by flexion of the same. Drive arm (14) engages fixed upright (12) at drive arm/upright pivot (15), which pivot point may be affected by use of a bolt or fastener or other means known in the art.

A hydraulic cylinder (16) is provided for engagement between the fixed upright and the drive arm as more specifically set forth below, the hydraulic cylinder (16) to provide resistance to the pivot action (driven by the exerciser) of the drive arm (14).

It is seen with respect to FIGS. 2 through 11 that hydraulic cylinder (16) is comprised of a body (18) having a removed end (18A) and a piston assembly (20) including a piston plunger or rod (22) having a removed end (22A). Further, it is seen that removed end (18A) of body (18) is pivotally mounted to upright (12) or the frame, for example (but not necessarily) on a standoff (13). Moreover, it is seen that Applicant provides a novel engagement of removed end (22A) of the rod (22), attaching the rod to both a point on the upright through the use of a rocker link (26) and to a point on the moveable drive arm (14) through use of a coupler link (24). It is seen that rocker link (26), through its length, the radius of curvature transcribed by removed end (22A). Further, it is seen that the geometry of the cylinder/frame/drive arm will change as the drive arm is pivoted, thus changing the MA of the system.

More specifically, it is seen that Applicant provides for a hydraulic cylinder (16) that is pivotally coupled at a first end to the fixed upright or frame of an exercise machine and, at a removed end of the plunger of the hydraulic cylinder, is pivotally coupled through a member to the upright and which removed end is also pivotally coupled to the drive arm through a second member. The net effect of using such a “4-bar” mechanism is to provide a variable resistance to the exertion force of the user muscles which variable resistance most closely matches the variable torque provided by the general strength of a typical user throughout the angular movement of the drive arm so as to effect a smooth constant angular velocity (“balance”) between the general strength of the user and the resistance of the machine through the angular positions between flexion to extension.

Note in FIGS. 5 through 7 and 8 through 10, alternate preferred embodiments, a number of additional/alternative features. In the embodiment illustrated in FIGS. 5 through 7, means, here holes (28) are provided in the drive arm such that the coupler link (24) may be adjustably positioned along the drive arm so as to effect a change in mechanical advantage and balance between the user's general muscle strength and the resistance provided by the machine. Further, holes (29) may be provided where the rocker link engages the frame or upright as in FIG. 2 for further adjustment. A slot and fastener arrangement known in the art (not shown) may be used in place of holes (28/29). The fasteners known in the trade can be used to fasten any of the pivot or joints set forth in all the embodiments to the invention and may be used to adjustably set the location of the coupler link along the drive arm.

FIGS. 5 through 7 and 8 through 10 also illustrate that the removed end of the rod may be attached, instead of to the removed ends of the coupler and rocker link as set forth in FIG. 2, the plunger may be pivotally engaged with one or the other of the coupler link (FIGS. 8 through 10) or rocker link (FIGS. 5 through 7).

Further, standoffs may be provided on the drive arm to pivotally mount the coupler link thereto. Likewise, standoffs are illustrated in all of the embodiments, to provide attachment of the rocker link to the upright, however standoffs need not necessarily be used.

While the preferred embodiments show single coupler links and single rocker links, of course they could be a pair adjacent to one another to form the same link that is achieved with a single bar member. Further, as seen in FIG. 11, there could be in a preferred embodiment left hand and right hand drive arm engagement assemblies (34) attached to the removed end of a single drive arm. FIG. 11 also shows seat (36) and upper arm rest (38).

The machine's resistance response increases nonlinearly with increasing velocity at each joint position. However, due to the force/length properties of muscle, the strength capacity of the elbow decreases with increasing angular velocity. During exercise, the machine naturally operates at the angular velocity where the machine resistance intersects strength capacity for the joint at each elbow angle.

To achieve balance between machine resistance and participant's strength, prior art machines have been modified so that the natural operating speed would be theoretically constant throughout the range of joint motion. The use of Applicant's novel 4-bar mechanism results in operating speeds (angular velocity and degrees per second) nearly constant over flexion angles from less than 20 degrees to greater than 120 degrees indicating an improved balance between resistance response of the machine and generalized strength of the user.

Applicant's cylinder provides increased force response to increased displacement velocity—indeed almost quadratically. That is to say, if one attempts to pivot the drive arm at a greater velocity, the cylinder responds nonlinearly, indeed almost quadratically to increase the resistance force. This is important in that a relatively weak user and a relatively strong user will achieve generally similar angular velocities even with a difference in the torque applied to the machine.

While the extension and flexion device is illustrated here with respect to flexion and extension the arm at the elbow, in fact it could be used with any type of machine, including those exercising the legs, knees, chest press/back pull, abdominal rotation, or other parts of the body. Furthermore, in place of a hydraulic cylinder a friction type device such as friction belt or the like or other velocity dependent (more resistance with increased velocity of drive arm) resistance means could be used.

Further, the specifications disclose a method of providing a friction device, such as a hydraulic cylinder, which friction device may include a resistance rod or arm. The novel method will affix one part of the friction device (such as the body of an hydraulic cylinder) to the frame of the exercise arm and link the resistance arm pivotally to both the frame of the machine and the machine user activated drive arm.

While upright (12) is illustrated, it is intended to cover any stationary part of a frame of the machine, and it need not be vertical.

The illustrations show a dampener with a removed end of the plunger mounted as set forth with the two links. However, it is also possible to mount the cylinder so that the removed end of the body has the coupler and rocker links engaged therewith.

Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the inventions will become apparent to persons skilled in the art upon the reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention. 

1. An exercise machine comprising: an upright; a drive arm pivotally mounted to the upright; a cylinder having a body and a piston including a plunger with a removed end thereon wherein a removed end of the body of the cylinder is attached to the upright; a first member for pivotal engagement with the upright and pivotal engagement with the removed end of the plunger; and a second member for pivotal engagement with the drive arm and the removed end of the plunger.
 2. The exercise machine of claim 1 wherein the upright is part of a frame and the frame includes a seat to support the exercise machine user.
 3. The exercise machine of claim 1 wherein the drive arm includes removed end, and at the removed end of the drive arm there is a limb engagement assembly.
 4. An exercise machine comprising: a frame adapted to rest on a support surface; at least one movable drive arm for pivotal engagement with the frame; a dampener having a first end and a second end, the dampener including a dampened, movable rod and a body, the body of the dampener for attachment to the frame; a first link for pivotal engagement to the frame and pivotal engagement with the first end of the dampener; and a second link for pivotal engagement to the drive arm and pivotal engagement with the first end of the dampener.
 5. An exercise machine comprising: a frame; a drive arm pivotally mounted to the frame; a cylinder having a body and a piston, including a plunger with a removed end thereon, wherein a removed end of the body of the cylinder is attached to the frame; a rocker link having a first end pivotally attached to the frame; and a coupler link having a removed end pivotally attached to the drive arm, the rocker link and the coupler link pivotally attached to said removed end thereof, the rocker link and coupler link comprising a rocker link and coupler link assembly; wherein the removed end of the plunger engages the coupler rocker link assembly
 6. An exercise machine comprising: a frame; a drive arm pivotally mounted to the frame; a two member assembly having a first member with a removed end and a near end and a second member with a removed end and a near end, the removed end of the first member pivotally attached to the frame, the removed end of the second member pivotally attached to the drive arm, the two members pivotally attached to one another; and a resistance mechanism having a first end pivotally mounted to the frame and a second end mounted to the two member assembly.
 7. The exercise machine of claim 6 wherein the resistance mechanism is a hydraulic cylinder.
 8. The exercise machine of claim 6 wherein the resistance mechanism engages, at the second thereof, one of the first or the second members.
 9. The exercise machine of claim 6 wherein the second end of the resistance mechanism is engaged to both the first and the second members of the two member assembly at the near ends thereof.
 10. The exercise machine of claim 6 wherein the two member assembly includes a standoff for receipt of the resistance mechanism thereto.
 11. The exercise machine of claim 6, further including a fastener and wherein at least one of the near ends of the two member assembly includes a multiplicity of holes for receipt of the fastener therein, which fastener is adapted to engage at least one hole in the other of the near ends to pivotally engage the near ends of the two members one to the other.
 12. The exercise machine of claim 6 further including a fastener and wherein the drive arm contains at least one hole therein for receipt of the fastener therethrough, the fastener for pivotal engagement with the removed end of the second member of the two member assembly.
 13. The exercise machine of claim 6 further including a fastener and wherein the frame contains a multiplicity of holes for receipt of the fastener therein for pivotal engagement with removed end of the first member of the two member assembly.
 14. The exercise machine of claim 6 wherein the first member and the second member are pivotally attached at the near ends thereof.
 15. An exercise machine comprising: a frame; a drive arm pivotally mounted to the frame; a two member assembly having a first member with a removed end and a near end and a second member with a removed end and a near end, the removed end of the first member pivotally attached to the frame, the removed end of the second member pivotally attached to the drive arm, the two members pivotally attached to one another; a resistance providing device having a first end pivotally mounted to the frame and a second end mounted to the two member assembly, wherein the resistance providing device is a pneumatic or hydraulic cylinder; and wherein the first member and the second member are pivotally attached at the near ends thereof. 